SALINAS >> Two Monterey County agencies have joined ranks to collect water data for wells in the Salinas Valley, an effort to hold off the state from coming in to regulate the over-pumping of groundwater supplying much of the county’s $4.4 billion agricultural economy.

The two agencies — the Monterey County Water Resources Agency and the Salinas Valley Basin Groundwater Sustainability Agency — have separate missions but both are concerned with water quantity and quality within the Salinas Valley Groundwater Basin, which is a series of smaller aquifers that span the entire 90 miles of the Salinas Valley.

A couple of those aquifers, called subbasins, are considered in “critical overdraft” by the state Department of Water Resources because of a century’s worth of over-pumping. The state defines critically overdrafted basins as those in which the continuation of current practices would likely result in significant adverse environmental, social or economic impacts.

A couple of those basins in southern Monterey County are not in overdraft so the task of the agencies is to maintain those water levels to prevent them from becoming over-drafted, said both Ara Azhderian, the Water Resources Agency general manager, and Piret Harmon, the Sustainability Agency’s general manager.

“By aligning our efforts to collect and share groundwater data, we are eliminating redundancy, streamlining local water management and providing the public with clearer, more accessible information,” Harmon said on Tuesday. “Transparency is a cornerstone of responsible groundwater stewardship, and this joint initiative helps ensure that residents, growers and policymakers alike have the tools they need to make informed decisions”

Many basins in the state are in overdraft, which in 2014 prompted the passage of the Sustainable Groundwater Management Act. That act requires every water basin in the state to become sustainable by 2042. Two of the critically overdrafted sub basins in Monterey County must reach sustainability two years earlier in 2040.

The local Sustainability Agency had its plan accepted — technically, six plans, one for each subbasin — in April 2023.

One of those overdrafted subbasins, named the 180/400 Aquifer Subbasin, referring to the number of feet underground they exist in, is not only in overdraft but is also experiencing seawater intrusion. Some wells in northern Monterey County have had to be taken offline because of the salinity levels, which will harm or kill crops. Brackish water has been detected as far inland as seven miles from the coast.

While the hydrology of intrusion is complex, overdrafting is the primary cause. Removing water from an aquifer decreases pressure and invites seawater to move in to fill the void. To combat the intrusion, the Water Resources Agency constructed projects, including the Castroville Seawater Intrusion Project, or CSIP, that uses treated recycled water or Salinas River Water from a small inflatable dam that growers in the north can use on crops rather than pumping groundwater.

The joint monitoring will collect data that will help the agencies meet the 2042 deadline by better understanding the dynamics of the overdrafting. The agencies are faced with either pumping less or providing additional water sources.

Over the past decade growers have reduced water use by instituting more accurate irrigation methods like drip lines as well as better understanding of crop management, such as optimum times and amounts to irrigate. Growers, particularly younger growers, are coming out of such schools as Cal Poly or U.C. Davis and are harnessing science to more efficiently manage crops.

The other side of that equation is increasing source water to reduce pumping. There are a number of ideas being knocked around, such as borrowing a page out of the Monterey Peninsula’s efforts to curb overdrafting the Seaside Basin by receiving excess winter flows from the Carmel River and injecting that into the Seaside Basin for later extraction, called Aquifer Storage and Recovery.

But the much larger Salinas River would create challenges of its own, particularly in the volume of water that can flow in the winter. The winter and spring 2023 Salinas River floods are testament to the potentially destructive force of the river. Those floods cost growers an estimated $1 billion.

Outwardly it seems that the more water the better. But massive infrastructure would be needed to capture and inject such flows. And as history has shown, the Salinas River is subjected to both heavy rains and debilitating droughts, yet the infrastructure would need to be engineered to address both, and that would cost an untold amount of money.

Another option is to somehow tie into the water generated by California American Water Co.’s desalination project. But the project could take a decade to construct and with all of the legal challenges and regulatory hurdles, seeing the plant reach fruition is not guaranteed.

If the state has to step in to manage the overdraft, it could order a halt to a significant amount of pumping, forcing acres of crops out of production. That, in turn, would result in a massive hit to county revenue and employment.

Water officials have known about the problem of overdraft for many decades. They now have 15 years to fix it or the state will.